Transparent sheet



Patented May 9, 19

UNITED STATES PATENT OFFICE MABINO GEN'T'ILE, OF CHICAGO, ILLINOIS, ASSIGNOB, BY DIRECT AND MESNE ASSIGN- IEN'I'S, OF ONE-HALF TO SAMUEL W. WEIS, ONE-FOURTH TO GEORGE PICK, AND ONE-TWENTIETH TO HERBERT I. SHERWOOD, ALL OF CHICAGO, ILLINOIS maansrnnnnm SHEET No Drawing. Application filed June 26,

This invention relates to transparent sheets, films or containers such as are extensively used for wrapping or containing 7 food and other products in sanitary display packages, for providing windows 1n window envelopes, and for various other purposes and apphcations. The main object of the invention is to provide a sheet, fihn or container for such purposes as those above indicated that can be made at a very low cost, shall be highly'transparent, shall possess the strength, durability, and general efliciency of more expensive articles employed for the same purposes, and'sufliciently moisture and grease proof to be practical.

In carrying out my present inventionv I- take a sheet of thin'paper as the base, preferably a soft, absorbent tissue, and this sheet I treat with a solution of cellulose nitrate dissolved in a suitable solvent such as ethyl acetate or amyl acetate, sufiicient in amount to yield a suitable flowing solution. To this cellulose nitrate solution is then added a non-hygroscopic material which causes the treating solutlon to penetrate the paper base, and also renders the product soft and pliable when dry. Materials which satisfactorily serve these purposesare castor oil and tri cresyl phosphate but other materials 1929. Serial No. 373,951.

chiefly as embodied in sheet form, I do not limit it to such form but include within the spirit and purview of the claim molded or I paper base. 7

. MARINO GENTILE.

possessing similar functional characteristics ma be employed. a

he treating solution can be applied to the aper base in an suitable manner, as by pping the base sheetin, or drawing it through a body of the treating solution, or

by flowing the latter over, or brushmg,

spraying or printing it on, the base sheet. The solution thoroughly penetrates and impregnates the fibrous structure of the base, and the latter is then dried. The residual product is a tough, flexible sheet highly transparent rendering completely visible obects covered thereby, non-porous and impervlous to dust, grease and moisture, and thus well adapted to serve the purpose of a sanitary wrapper or container especially for food products, pharmaceutical products, and the like, and low in cost of materials and manufacture.

While I have described the invention 

